.container div div{
    color: rgb(0, 0, 0);
    text-align: center;
    line-height: 100px;
    width: 100px;
    height: 100px;
    background: #dedede;
    border: 1px solid red;
}
.static{
    position: static;
}
.relative{
    position: relative;
}
.absolute{
    position: absolute;
}
.fixed{
    position: fixed;
}